Warm fall, winter expected after 10th-hottest summer

Jack McMenamin, 4, of Pennsauken, plays in the sand Friday at 7th Street on the last day of summer in Ocean City.

Summer may not have seemed as hot in South Jersey as in past years, but it still ranks as the 10th-warmest on record at Atlantic City International Airport in Egg Harbor Township.

With today being the first day of fall, the questions meteorologists and climatologists hear center on the lasting impact from a year of extreme weather — including a long-lasting broiling drought in the Great Plains — and what kind of of weather the coming fall and winter months will bring.

The autumnal equinox occurs about 10:30 a.m., several days after the National Oceanic and Atmospheric Administration confirmed that the lack of Arctic ice shattered records this summer, covering less than half of what the the ice sheet encompassed in the early 1980s.

“In terms of the overall temperature, several factors are indicating — at least that the climate prediction center is analyzing — would suggest that there would be slightly higher chance of above-normal temperatures this upcoming fall and winter seasons, as well,” National Weather Service meteorologist Mitchell Gaines said. “But, of course, a lot of short-term factors play in that we don’t know until a couple weeks in advance.”

Most of the National Weather Service’s seasonal forecasts are tailored for large regional areas, but Gaines said there are a few factors that affect South Jersey specifically.

“In terms of water temperatures, often the Atlantic Ocean and the Delaware (Bay) play a role in storms; whether they’re producing rain or snow,” he said. “If there’s a lot of warm water still around, it could also lead to a warmer system. Also, in the case of warmer water, it will allow systems to strengthen as well, which could lead to more precipitation.”

He said there is no forecast for those water temperatures in the upcoming seasons.

A number of large scale oceanic and atmospheric patterns come into play for determining our weather, Rutgers University professor and New Jersey State Climatologist David Robinson said.

Forecasters are predicting that cooler-than-normal eastern Pacific Ocean temperatures — a phenomena known as El Nino — are expected to form, Huug van den Dool, a meteorologist with the NOAA’s Climate Prediction Center, said during a teleconference call Thursday. The El Nino expected to form will be weaker than initially forecast, van den Dool said.

El Nino winters tend to be more volatile and bring more storm systems across the U.S., mostly affecting the southeastern and mid-Atlantic states, Robinson said.

Whether those storms are cold enough to bring snow this winter or even travel up the East Coast in a northeaster storm depends more on an atmospheric condition known as the Northern Atlantic Oscillation, which can’t be predicted more than a couple of weeks in advance, he added.

Another Rutgers scientist, Jennifer Francis, has researched how the changing Arctic sea ice is affecting weather patterns in the Northern Hemisphere, including those in New Jersey.

The cold temperatures in the Arctic interact with the warmer temperatures of the middle latitudes to give strength to the jet stream, which is an upper-atmosphere air current that drives major weather patterns, Francis said. As the Arctic warms due to climate change, the decrease in the temperature differences causes the jet stream to weaken and, more importantly, slow down and change shape such that it blocks weather patterns into place, Francis said.

“What we think might happen for not just our area on the East Coast, but all over the Northern Hemisphere, we should expect to see weather systems that hang around longer,” Francis said.

What’s unusual about the discovery is that it’s one of the first confirmed links between the extreme weather experienced across the Northern Hemisphere and the decreasing Arctic sea ice, Francis said.

Another factor in storms this coming fall and winter will be the unusually warm ocean temperature. The NOAA announced earlier this week that water temperatures the first six months of the year the northwestern Atlantic Ocean, from Maine to North Carolina, were the highest on record. State researchers also found that off the coast of New Jersey, the water temperature was unusually warm from top to bottom.

While the temperature now is more in line with the average, the question will be how much the water cools off into fall and winter.

Those warmer temperatures mean there is much more heat stored in the water and it will take longer for temperatures to drop this winter, Robinson said.

While June was the first month since January 2011 at Atlantic City International Airport in Egg Harbor Township to have a below-average monthly temperature, the summer overall still ranks as the 10th-warmest on record. Statewide, the temperature has been above average for 19 months straight, Robinson said.

This year also ranks ninth in the number of days the temperature reached or exceeded 90 degrees, according to the National Weather Service, and third for the number of days the temperature reached or exceeded 100 degrees.